Nuclear weapons are an existential threat to humanity, and must never be used again, under any circumstances. We therefore welcome the recent shift in the international discourse about nuclear weapons towards the recognition by a number of States that the catastrophic and irremediable consequences of the use of nuclear weapons require decisive action to outlaw and eliminate them.

The nature and scope of the medical, environmental, and humanitarian disaster that would result from any use of nuclear weapons was examined in detail at the Oslo conference on the Humanitarian Impact of Nuclear Weapons in March 2013, and will be the subject of a follow-up conference this February in Mexico.

We know, from the tragic experiences of Hiroshima and Nagasaki, that even a single nuclear weapon exploded over a city can kill tens of thousands of people in an instant and leave tens of thousands more with untreatable blast, burn, and radiation injuries. More recently, we have learned that a limited, regional nuclear war involving 100 Hiroshima-sized weapons—a fraction of current global arsenals—would disrupt the Earth’s climate and curtail agricultural production so severely that more than a billion people would be at risk of starvation from the resulting “nuclear famine.” A conflict employing the large arsenals of the US and Russia—which cannot be ruled out as long as the weapons exist—would threaten the very existence of everyone on Earth.

The continued possession of over 17200 nuclear weapons by nine countries, together with large amounts of fissile material with attendant proliferation risks, poses a real danger to the existence of humankind. The use of nuclear weapons by design or accident and by possessor states or nonstate actors threatens all of us.

The dangers that we face from nuclear weapons—and the humanitarian imperative to outlaw and eliminate them—have become a major focus of several official and unofficial gatherings of States in the past year, including preparatory meetings for the 2015 Non-Proliferation Treaty Review Conference, the meetings of the Open-Ended Working Group on nuclear disarmament, and the High-Level Meeting on Nuclear Disarmament at the UN General Assembly on September 26. We urge those States to take the next step and to initiate a process for a treaty that will ban nuclear weapons and, ultimately, abolish them before they abolish us.

UN Secretary-General Ban Ki-moon has said “there are no right hands for the wrong weapons.” This new humanitarian-based initiative to remove the most abhorrent weapons ever created from everyone’s hands, which is now supported by a growing number of States and by civil society, offers a pathway to a nuclear-weapons-free world that is inspiring, hopeful, and practical. We give this initiative our full endorsement.